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Fortigate 80e and 60e console bootloader output garbled

Forum|Forum|1 year ago
June 8, 2025
6 replies
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I am trying to connect to a fortigate 80E running 7.4.7 to roll back a software version but I am having difficulty connecting to the console during the boot process.

I can connect to the console port via putty when the Fortigate 80e is booted and up and running. Putty is set to 9600 8 n n 1

But when the system boots, the system outputs odd characters until the boot process is complete, then I get the login prompt

I read that the Baud rate changes to 115200 during the bootloader stage and then returns to 9600. However, I have tried changing putty to 115200 and rebooting and I still get garbled output.

I have tried 9600, 19200, 38400, 57600, and 115200 but all output bad characters.

I have also tried a FortiGate 60E, which has the same issue.

I have also tried a FortiGate 90D at 9600 and this works just fine.

What are the correct settings for an 80e running 7.4.7?

What else can I try?

I don't understand why this is so dificult

FortiGate

Best answer by londonnet

So this was an odd one. In short it was my usb serial adapter.

I had purchased what I thought was a cisco original but turned out to be a copy. Although on some devices it worked perfectly at 9600 and 115200 90d for example on an 80e and 60e at boot only it failed.

I then purchased a fortinet original usb console adapter and it works just fine.

I'd be really interested to know if there is something proprietary about the fortinet USB serial adapter, I spent a lot of time trying to work this out.... Some of it was fun I guess, I like a puzzle

Hope this helps others

AEK

SuperUser

Can you share this output?

show full-configuration sys console

From my side I never had an issue when using the default putty config:

AEK

londonnetAuthor

New Member

To be clear, when I am connected to a fully booted 60e 0r 80e at 9600 I have no issues. It is only during the boot process that I have the issue. I read that during the boot process, the Baud rate changes to 115200, which I have tested but it doesn't work.

However, on a 90d I see a perfectly formatted output at 9600 during boot. I have tested on a 90d by setting it to 115200 and again, this works perfectly

Output with from putty at 9600 during boot

WT
()'▒ H\MC
" Q (LI@hJhW&t5RVHRJ,"P W@,dx(
B(
Dh+
4▒^B
KA* A
&@h@+[# A
hLhPB SCHDhRV Q$@QSC.RD
k

WY]NJjU@&H Z

xxxx # show full-configuration sys console
config system console
set output more
set login enable
set fortiexplorer enable
end

xxxx #

Appreciate any thoughts or things I can check.

Thanks

londonnetAuthor

New Member

Has anyone else seen this issue? Not present on D Series units only seen of E series

londonnetAuthor

New Member

Is anyone else having this issue? Is there any other way of restoring an older fw other than via the gui? 7.4 has stopped me from being able to move between versions for testing

londonnetAuthorAnswer

New Member

So this was an odd one. In short it was my usb serial adapter.

I had purchased what I thought was a cisco original but turned out to be a copy. Although on some devices it worked perfectly at 9600 and 115200 90d for example on an 80e and 60e at boot only it failed.

I then purchased a fortinet original usb console adapter and it works just fine.

I'd be really interested to know if there is something proprietary about the fortinet USB serial adapter, I spent a lot of time trying to work this out.... Some of it was fun I guess, I like a puzzle

Hope this helps others

Toshi_Esumi

SuperUser

FTNT's console cables connect only 3 lines/pins electronically, while Cisco console cables connect 8 lines/pins.
https://pdfcoffee.com/fortinet-cable-consola-pdf-free.html
https://www.cable-tester.com/rj45-rs232-console-cable-pin-out/

Depending on the hardware/chip on the device, it might not like the voltage coming through Cisco console cable on those lines, RTS/DSR/DTR/CTS, while they're always "open" other than those three lines/pins with FTNT console cable.
I so far never had problem with Cisco console cable when I connected to various types of FGTs, like 40C/50E/60D/60E/60F/40F/70F/100F/1000D/1500D/1000F, etc. However FS108F definitely doesn't work while FS224D works fine. The chip or circuit design must be different with that particular small newer FSW.

Toshi

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